Gunnery practice device



Patented Aug. 14, 1945 GUNNERY PRACTICE. DEVICE Tord Olof RichardDahlberg, Nockeby, and Karl Matts Vigborg', Stockholm, Sweden, assignorsto Kooperativa Forbundet Forening U. P. A.,

Stockholm, Sweden Application February 16, 1943, Serial No. 476,042 InSweden October-28, 1940 3 Claims.

The present invention relates to a gunnery practice device, and moreparticularly, to a device for practicing the control of anti-aircraftguns of the type in which the altiudinal and the azimuthal adjustmentsare effected by different directors.

One object of the present invention is to provide a gunnery practicedevice of the type described which can be mounted on the barrel of a gunand which includes model targets adjustable relative to the gun sightsin altitudinal and in azimuthal direction.

Another object of, the invention is to devise a practice mechanism inwhich each of the two directors operating the altitudinal and theazimuthal adjusters, respectively, observes a difierent model target,and two model targets being, however, controlled in unison by theinstructors.

A still further object of the invention is to provide a gunnery practicedevice mounted on a gun barrel and including model targets which can bedisplaced relative to the gun barrel and sights by the instructor in anydesired altitudinal or azimuthal direction, without any change in theposition of the barrel, said same targets being displaced in theopposite directions, so as to reduce the displacements effected by theinstructor to zero, upon operation of the gun barrel directing mechanismby the directors in a way to follow the apparent movements of thetarget.

These and other objects which will appear more clearly as thespecification proceeds are accomplished by the arrangement andcombination of parts set forth in the following detailed description,defined in the appended claims and illustratively exemplified in thesingle figure of the accompanying drawing which is a diagrammaticperspective view of one embodiment of the invention.

The drawing shows a gunnery practice device applied to an anti-aircraftgun provided with a central seat for an instructor and two lateral seatsS and H to be occupied by two trainees or directors. Two diopter ortelescopic gun sights, shown diagrammatically in the drawing aremounted. on the gun for the directors operating the direction handle Soto effect azimuthal adjustments of the gun and the elevation handle Hz;to effect altitudinal adjustments of the gun, respectively. The practicedevice comprises two miniature targets in the form of model aeroplanesSm and Hm which are mounted in front of the sights Ss and H5,respectively, by means of short vertical rods I formed at the ends of anelongated target support 3 extending at substantially right angles tothe optical axes of said sights so that each director when sitting inhis seat (S, H) can observe the corresponding target figure (Sm. Hm) byleaning over and looking through his gun sight (Ss, Hs). The elongatedsupport 3 is, at its center, rigidly connected with the forward end of atube 2.

The tube 2 is connected with the barrel E of the gun by a suitablefitting 4, and it is movable relative to said barrel and fitting on apivot 5 in two planes which are at right angles to one another. Withinthe tube 2 there is a nut 6 traversed by a screw .8 which is rotatablymounted in a yoke l. 27 is a counterweight displaceable in the tube 2.The screw 8 carries a bevel gear wheel 9 cooperating with a bevel gearwheel H which is driven from a shaft H]. To the yoke 7 is fixed a sleevel2 with internal screw thread engaged by a screw l3. To screw 53 isfixed a bevel gear wheel 14 which is in driving mesh with a bevel gearwheel [6 fixed to a shaft IS. 'The gear wheels I4 and It, the screw l3and the shaft l5 are mounted in a frame I! fixed to the barrel E, whilethe gear wheels 9 and H are mounted in bearings formed in the yoke l.The shaft Ill and also the shaft l5 may be flexible shafts, if desired.Suitable guide members which form a part of the frame ll but which havebeen omitted from the drawing for the sake of clarity are provided toguide the yoke I vertically.

As shown each of the shafts Ill, 15 extends into a differential gearcasing l8 and has a differential bevel gear wheel l9 fixed to its endinside said casing. Other bevel wheels 20 are fixed to the casings l8and are in mesh with gear wheels 2| secured to shafts 22 which, at theturning of the handle Sc and Ho respectively, are rotated by gears 23connected with said handles. By means of two handles 02) the instructor,when seated in his seat 0, may via the differential gears, set thewheels l9, and the shafts l0 and 55 respectively, in rotation. Thescrews 8 and 13 are actuated during this rotation, and. the tube 2 willswing in the vertical as well as in the horizontal direction i. e. thetarget figures Sm and Hm will move. Consequently, the directorsoperating the gun aiming mechanism must now catch the target figures byturning the handles S2) and Ho so as to retain the figures on therespective lines of sight. This result is accomplished if the motions ofthe handles So and H12 are so dimensioned with respect to the motions ofthe handles 01) that the resulting displacement of the tube 2 withrespect to the gun barrel E is zero. The instructor can easily ascertainthis by switching on a lamp L fixed to the barrel E by a bracket 24,because if the setting is correct, the pencil of rays of said lamp willpenetrate a sight plate V located between a movable indicator formed bya third target figure Om mounted centrally on the support 3 and the lampL and catch the figure Om. The lamp L being concealed from thedirectors, the ignition of the lamp introduces an element of surprise.To guide the tube 2 while the directing motions are carried out ayoke-formed part 25 is connected with the fitting 4, the bent outerportions of said part insuring that the tube does not turn around itslongitudinal axis by engaging the ends of a transverse member 26connected with the tube 2.

Thus, the above described system of motion makes it possible to impartto the difierent target figures motions relatively to the barrel E intwo planes which are at right angles to one another, and the combinationof motions within these two different planes is sufficient to impartuniversal motions to the target figures, said motions corresponding tothe motions of real targets. It will be seen that, whatever motion maybe imparted to the model targets from the seting means 01) operated bythe instructor, a proper cooperation of the two independent controlmechanisms Hz; and So by the directors will bring each model target intoand hold it in the field of the corresponding sight while the gun barrelcarries out the movements induced by the operation of the handles Hz;and S2). Both model targets Hm and Sm which are fixed to the commonsupport 3 and always move in unison, represent only one single actualtarget. At the distance of an actual target, the optical axes of the twotelescopic sights merge, so that a target which is in the field of onesight appears also in the field of the other sight. This, however, isnot true at the short distance from the sights at which the modeltargets are arranged, according to the present invention, and it is,therefore, necessary to represent the single actual target in front ofeach sight by a separate small scale model. The instructor by operatingthe handles 01; imparts to both models Hm and Sm exactly the samealtitudinal and azimuthal displacements relative to the correspondingsights. The directors must cooperate to compensate for these twodisplacements so as to hold each model inthe field of associated sight,exactly as in aiming at an actual target the director effecting thealtiudinal adjustment must cooperate with the director effecting heazimuthal adjustment to hold the single actual target in the field ofboth telescopic sights. By providing the shafts 22 with frictioncouplings, fOr example in the way shown in the drawing, where the gearwheel 23 is rotatably mounted on its shaft 22, and i pressed by a springagainst a disc 28 fixed to the shaft 22, it is possible to swing thebarrel quickly to any position determined by the instructor and when theposition in question has been reached the instructor grasps the handles02) and then the directors will have to catch and follow the targetfigures. The drill can then be quickly interrupted and quite on oppositesetting of the barrel can be ordered, and the catching and following ofthe target figures can be resumed.

The device may also be applied with advantage in a central fire controlinstrument with the same arrangement except that the shafts 22 will bein driving connection with the members adjusting the two forward sights,said members thus corresponding to the handles So and Ho in the drawing.

Several embodiments are, of course, possible within the scope of theinvention. Particularly the members adjusting the rod 2 may be varied ina great many ways without departing from the basic idea of theinvention.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. A gunnery practice device for application to an aiming mechanismincluding an adjustable member adapted to be trained upon a target andcarrying two parallel telescopic sights for use in the altitudinal andin the azimuthal adjustments, respectively, of said member, said devicecomprising a single elongated target support mounted on said adjustablemember in front of said two sights at substantially right angles totheir optical axes, two model targets mounted on said support at a fixeddistance from each other equal to that between the optical axes of saidsights, setting means for imparting to said target support selectedaltitudinal and azimuthal movements relative to said sights, a firstindependent control mechanism arranged for operation by a directorlooking through one of said sights to impart to said target supportselected altitudinal movements relative to said sights which may serveto compensate for the altitudinal components of the movements effectedby said setting means, and a second independent control mechanismarranged for operation by a second director looking through said secondsight to impart to said target support selected azimuthal movementsrelative to said sights which may serve to compensate for the azimuthalcomponents of the movements effected by said setting means, whereby,upon a proper cooperation of both said control mechanisms, each of saidmodel targets may be brought into and held in the field of thecorresponding sight.

2. A gunnery practice device, as claimed in claim 1, in which'each ofsaid control mechanisms comprises a differential gear and means foractuating one member of said differential gear, and said setting meansincludes means for transmitting torque to other members of said twodifierential gears.

3. A gunnery practice device, as claimed in claim 1, including a movableindicator mounted on said target support in a fixed spatial relation tosaid model targets, and a fixed indicator mounted on said adjustablemember in the vicinity of said target support and in a correspondingspatial relation to the optical axes of said sights, whereby an axialcoincidence of said movable indicator with said fixed indicatorindicates a correct adjustment of both said control mechanisms.

TORD OLOF RICHARD DAHLBERG. KARL MA'I'IS VIGBORG.

